Question: $ { \left[\begin{array}{rr}{1} & {0} \\ {-1} & {-2}\end{array}\right]-\left[\begin{array}{rr}{1} & {-1} \\ {4} & {-2}\end{array}\right] = {?} } $
To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{1}-{1} & {0}-{-1} \\ {-1}-{4} & {-2}-{-2}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{0} & {1} \\ {-5} & {0}\end{array}\right]}$